That Shakespeare could not have built up his recital from an imaginative transformation of Plutarch’s hints seems precluded by an examination of the various sources already mentioned. These contain the substance of the non-Plutarchian matter; it remains to establish Pescetti’s claims against this evidence.
While there is a striking agreement as a whole in the various accounts of the classic writers, no single one contains all the omens recorded by Shakespeare. Pescetti, however, not only has the most comprehensive extant record but he accompanies his account with individual touches which seem reflected in Shakespeare’s subsequent treatment.
An examination of the portents mentioned by Shakespeare reveals the following which can be traced to Plutarch: the flaming hand; the men all in fire walking up and down; the bird of night at noon-day hooting and shrieking in the market place; the beast without a heart; the comet. In addition we have the following not indicated by the biographer: the tremendous storm; the earthquake; the raging seas referred to by Casca; the wild beasts roaming the streets; the civil strife in the heavens; the dead leaving their sepulchres; the battle in the clouds.
Taking the earthquake first, a comparison of the available sources reveals the following: Casca says to Cicero,
“Are you not moved when all the sway of earth,
Shakes like a thing unfirm?”
Vergil mentions the earthquakes in the Alps and the openings of the earth as portents of Caesar’s death.[[34]] Lucan[[35]] says “The Alps shook off their ancient snows,” while Lydgate[[36]] has
“Earthquaues sodayne and terrible
Ouertourned castels up so doune.”
In Ovid we read,